Topnotch and others have hinted strongly toward Avalanche Gray being revealed in a short period. It's showing up as a touch up paint option for the 2015 right now. Supposedly going to be a moderately light, polished gray color (non-metallic).

Considering I will be ordering a 2016 MY (unless the 2015 MY is freakishly long and they're still building new '15's in April of 2016)...
I would love it if they kept Guard! Its so close to Dark Highland Green.

But as far as new colors or "new" returning colors:
Grabber Blue
A darker silver, like the "Billet Silver" on the new Challenger.

Considering I will be ordering a 2016 MY (unless the 2015 MY is freakishly long and they're still building new '15's in April of 2016)...
I would love it if they kept Guard! Its so close to Dark Highland Green.

But as far as new colors or "new" returning colors:
Grabber Blue
A darker silver, like the "Billet Silver" on the new Challenger.

If I answered seriously I would've said the same thing. Dk Highland is the best Mustang color. I love Grabber blue & I they had a Billet Silver Challenger at the auto show this spring, definitely the best shade of silver I've ever seen.